/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */
package net.sf.freecol.common.networking;

import net.sf.freecol.common.model.Game;
import net.sf.freecol.common.model.Player;
import net.sf.freecol.common.model.Unit;
import net.sf.freecol.common.model.Role;
import net.sf.freecol.server.FreeColServer;
import net.sf.freecol.server.model.ServerPlayer;

import org.w3c.dom.Element;


/**
 * The message sent to equip a unit for a particular role.
 */
public class EquipForRoleMessage extends DOMMessage
{

    /** The identifier of the unit to equip. */
    private final String unitId;

    /** The Role identifier. */
    private final String roleId;

    /** The role count. */
    private final String roleCount;


    /**
     * Create a new <code>EquipForRoleMessage</code> for the supplied
     * Unit and Role.
     *
     * @param unit The <code>Unit</code> to equip.
     * @param role The <code>Role</code> to equip for.
     * @param roleCount The role count.
     */
    public EquipForRoleMessage( Unit unit, Role role, int roleCount )
    {
        super( getXMLElementTagName( ) );

        this.unitId = unit.getId( );
        this.roleId = role.getId( );
        this.roleCount = String.valueOf( roleCount );
    }

    /**
     * Create a new <code>EquipForRoleMessage</code> from a supplied element.
     *
     * @param game The <code>Game</code> this message belongs to.
     * @param element The <code>Element</code> to use to create the message.
     */
    public EquipForRoleMessage( Game game, Element element )
    {
        super( getXMLElementTagName( ) );

        this.unitId = element.getAttribute( "unit" );
        this.roleId = element.getAttribute( "role" );
        this.roleCount = element.getAttribute( "count" );
    }


    /**
     * Handle a "equipForRole"-message.
     *
     * @param server The <code>FreeColServer</code> handling the message.
     * @param player The <code>Player</code> the message applies to.
     * @param connection The <code>Connection</code> message received on.
     * @return An update encapsulating the equipForRole location change
     *     or an error <code>Element</code> on failure.
     */
    public Element handle( FreeColServer server, Player player,
                           Connection connection )
    {
        final ServerPlayer serverPlayer = server.getPlayer( connection );
        final Game game = server.getGame( );

        Unit unit;
        try
        {
            unit = player.getOurFreeColGameObject( unitId, Unit.class );
        }
        catch ( Exception e )
        {
            return DOMMessage.clientError( e.getMessage( ) );
        }
        if ( unit.isInEurope( ) )
        {
            ; // Always OK
        }
        else if ( ! unit.hasTile( ) )
        {
            return DOMMessage.clientError( "Unit is not on the map: "
                                                   + unitId );
        }
        else if ( unit.getSettlement( ) == null )
        {
            return DOMMessage.clientError( "Unit is not in a settlement: "
                                                   + unitId );
        }

        Role role = game.getSpecification( ).getRole( roleId );
        if ( role == null )
        {
            return DOMMessage.clientError( "Not a role: " + roleId );
        }
        int count;
        try
        {
            count = Integer.parseInt( roleCount );
        }
        catch ( NumberFormatException nfe )
        {
            return DOMMessage.clientError( "Role count is not an integer: " +
                                                   roleCount );
        }
        if ( count < 0 || count > role.getMaximumCount( ) )
        {
            return DOMMessage.clientError( "Invalid role count: " + roleCount );
        }

        // Proceed to equip.
        return server.getInGameController( )
                .equipForRole( serverPlayer, unit, role, count );
    }

    /**
     * Convert this EquipForRoleMessage to XML.
     *
     * @return The XML representation of this message.
     */
    @Override
    public Element toXMLElement( )
    {
        return createMessage( getXMLElementTagName( ),
                              "unit", unitId,
                              "role", roleId,
                              "count", roleCount );
    }

    /**
     * The tag name of the root element representing this object.
     *
     * @return "equipForRole".
     */
    public static String getXMLElementTagName( )
    {
        return "equipForRole";
    }
}
